This invention is directed to dishwashers and particularly those having upper and lower racks and separate spray arms associated with each rack. In the dishwasher of this invention as well as those of U.S. Pat. Nos. 3,180,348 and 3,854,762 and 4,266,565, all assigned to the assignee hereof, there is described a dishwasher having an upper rack on which is mounted a rotatable spray arm that is rotated by the reaction forces of spaced and inclined spray nozzles which also serve to spray washing and rinsing liquid over dishes held in the upper rack.
The rotatable spray arm is provided with liquid by an upwardly projected jet of liquid that enters a receiver and then flows into and through the spray arm, thereby providing the force necessary to project the liquid through the nozzles.
One of the problems with a dishwasher or similar article washing apparatus is the centering of the liquid receiver in the upper rack with respect to the axis of the projected jet, particularly when the axis of rotation of the spray arm and attached receiver is offset from the central axis of the projected jet.
In the above U.S. Pat. No. 4,266,565, there is disclosed a structure in which the entire upper spray arm and integral jet receiver is shifted laterally to accommodate this non-alignment so that the lateral shifting is intended to make the axis of rotation and the central axis of the jet coincide.
The most pertinent prior art of which applicant is aware are U.S. Pat. Nos. 1,053,715; 3,180,348; 3,363,950 and 3,876,148.
Of these, U.S. Pat. No. 1,053,715 discloses a rotary shaft B mounted for rotation in a bearing D, with the bearing having a capacity for movement about its horizontal axis for self-alignment.
U.S. Pat. No. 3,180,348 discloses a dishwasher with an upper spray arm receiver for an upwardly directed jet of liquid, the upper spray arm being manually adjustable for alignment.
U.S. Pat. No. 3,363,950 discloses a motor mounted on self-aligning bearings which are movable in the axis of rotation of the shaft.
U.S. Pat. No. 3,876,148 discloses means for mounting and moving a spray arm in a dishwasher so that the nozzles of the spray arm move in a non-repeating epicyclic spray path as a result of the mounting structure for the spray arm.